Shelf



FIG. 1 is the front perspective view of a shelf showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left-side view thereof;

FIG. 5 is a right-side view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 illustrates the shelf installed in an unclaimed environment.

The broken lines in the drawings show unclaimed environment only and form no part of the claimed design. 

CLAIM The ornamental design for a shelf, as shown and described. 